How do you unblock a blocked micro bore system?

Stumbled aross this site from Google, looks like some knowledgeable people on here so thought I'd pick your brains.

Recently I got two rads that went cold. On advice from a plumber I had the system flushed and all was well for about a week, then the problems really started!!

Out of 15 rads (all on 8mm microbore) only 1 works at about 80% warm. 6 rads are stone cold the rest are about 25-50% warm. I have removed all the rads and cleaned them out (some had quite a bit of sludge in them) but the flow pipes are offering little more than a trickle (with pump turned up full). Have run the system on Sentinal X400 for about a month now but nothing seems to be getting better and its cold!!

I've even tried attaching a sump drain to try and create a vacuum to pull any rubbish through but to no avail.

Can anyone advise on how I can a/. Find out what/where the problem is and b/. Suggest how to fix it.

PS My house is only 4 years old - Good to know a quality job was done by the builders (Wilcon homes)

sounds like your quite blocked up. its difficult to remove some blockages without cutting the pipes at various places. thats the best way.....but.....

have you tried wire down the pipes to push the blockages about?

i quite often use a foot pump on microbore to try and push the blockages. the foot pump nozzle is almost a perfect fit for 8mm pipe. if you do this when your header tank is still full and pump it up to 2-3 bar and then take off the pump nozzle and repeat it several times it sometimes loosens it....beware of black water coming out if it does clear it....and of course it wont stop until the system is empty!!!!!....its a kind of risky way of doing it but effective if your stuck and dont want to cut the pipes.

the above will only really work on soft blockages. if its gone all hard then forget it

if the system is not is non combi. you could reverse the pump with the boiler switched off ,to release the blockage before you start cutting pipes.
builders will use the cheapest sub-contractor regardless of quality

Wilcon you all till we`ve made a mint or

I can't speak for x400, but on really badly sludged systems Fernox DS40 is really capable of eating serious amounts of crud. You might try connecting a hosepipe to each rad feed and try blasting with mains pressure water. Otherwise as others have said, forget it and re pipe with proper 15mm copper.

Use fernox ds40.

And use a plumber that is not scared of it.

David